llvmPackages_12: Improve and extend the meta attributes

pkgs/development/compilers/llvm/12/lld/default.nix

@@ -1,4 +1,4 @@
-{ lib, stdenv
+{ lib, stdenv, llvm_meta
 , fetch
 , libunwind
 , cmake
@@ -30,10 +30,16 @@ stdenv.mkDerivation rec {
     moveToOutput lib "$dev"
   '';
 
-  meta = {
-    description = "The LLVM Linker";
-    homepage    = "https://lld.llvm.org/";
-    license     = lib.licenses.ncsa;
-    platforms   = lib.platforms.all;
+  meta = llvm_meta // {
+    homepage = "https://lld.llvm.org/";
+    description = "The LLVM linker";
+    longDescription = ''
+      LLD is a linker from the LLVM project that is a drop-in replacement for
+      system linkers and runs much faster than them. It also provides features
+      that are useful for toolchain developers.
+      The linker supports ELF (Unix), PE/COFF (Windows), Mach-O (macOS) and
+      WebAssembly in descending order of completeness. Internally, LLD consists
+      of several different linkers.
+    '';
   };
 }